Multiple primary cancers associated with hematological malignancies.

Two hundred and thirty-six cases of multiple primary cancer associated with hematological malignancies, collected from 35 medical institutions in Japan, are reported. Based on the time interval between the first cancer and the second cancer, they were divided into three groups: synchronous cancer (94 cases), metachronous cancer subsequent to hematological malignancy (61 cases) and metachronous hematological malignancy subsequent to carcinoma (76 cases). The most common initial cancers were acute leukemia (including atypical leukemia and erythroleukemia), non-Hodgkin's lymphoma, multiple myeloma and chronic myelogenous leukemia of the hematological malignancies, and gastric cancer of the carcinomas. Patients with cancer of the uterus and breast in the metachronous cancer group metachronously developed hematological malignancies more frequently than those in the synchronous cancer group. Multiple primary cancer was observed more frequently in men than in women both in the synchronous cancer group and in the group with metachronous cancer subsequent to hematological malignancies. Acute leukemia was the most frequent disease type in incidence among the metachronous hematological malignancies. This secondary acute leukemia was characterized by a mostly granulocytic nature, poor response to chemotherapy and poor prognosis.